This invention pertains generally to the field of milking equipment, and particularly to the milking claw used with the teat cup cluster that receives the milk from the animal being milked.
Modern milking machines, particularly those used for milking cows, have several teat cups (four for milking a cow) which are connected by hoses to the inlets of a milking claw. The claw has a bowl that acts as a temporary receiver for the milk from each of the teat cups. The bowl of the claw is connected to a milk hose to which a vacuum is applied to draw the milk out of the bowl and through the milking hose to, e.g., a common milk line which serves several milking stations in a milking parlor. In a conventional milking claw design, the milk inlets are mounted to a top side of the bowl and will be facing upwardly when teat cups are attached to the cow for milking, and an outlet is formed at the bottom of the bowl through which milk is drawn out via an outlet tube to the milk hose. An example of this conventional arrangement is shown in U.S. Pat. No. 5,080,041. To avoid certain problems encountered with bottom outlet milking claws, top outlet claws were developed in which an outlet tube extends from an intake opening spaced closely adjacent to the bottom of the bowl. The outlet tube extends upwardly through the top of the bowl to a position adjacent to the milk inlets, where it is connected to the milk hose. Examples of top outlet claws are shown in U.S. Pat. Nos. 4,136,639, 5,052,341, 5,076,221, 5,291,853, 5,988,105, 6,006,695, 6,058,880, D372,566 and D384,445.
Top outlet claws generally have the advantage of drawing the milk out of the milk claw bowl more or less continuously in small spurts, so that large slugs of milk are not drawn into the milk hose. In the typical top outlet claw, a vertical section of the outlet tube is covered by a cap which can be opened to allow inspection of the milk tube and particularly the weld joint at which a metal outlet tube is joined to the metal body of the bowl. Top outlet claws typically have a horizontal section of the outlet tube that extends at a right angle from the vertical section and is connected to the milk hose. As the milk exits the bowl through the outlet tube, it must turn a sharp right-angled corner to transfer from the vertical tube to the horizontal tube, resulting in turbulence in the milk flow. This turbulence can contribute to an undesirable pressure drop from the milking claw to the milk line and may unnecessarily agitate the milk as it passes through. The right-angle bend or cap assembly may also accumulate milk residue which must then be periodically cleaned out. Top outlet tube designs which curve from the horizontal section to the vertical section, rather than having a right-angle joint, have generally not been acceptable for sanitation purposes because the weld joint between the outlet tube and the claw body is not accessible for visual inspection. Top outlet claws draw milk to a greater height than bottom outlet claws, which may contribute to an undesirable pressure drop from the milking claw to the milk line. Top outlet claws also have all the hoses associated with the claw (milk inlet and outlet hoses, pulsation hoses and pulsation hose manifold) in the space above the claw between the milk inlets, which can congest this space and interfere with handling.
The milking claw of the present invention utilizes the benefits of conventional top outlet claws, with the outlet tube having an intake opening spaced closely adjacent to the bottom surface of the milking bowl, while providing a reduced pressure loss and smooth milk flow as the milk exits the milking claw. As milk enters the bowl of the claw, the intake opening is covered and uncovered many times per second as the milk is drawn out through the outlet tube in droplets rather than in slugs, providing efficient, continuous milk removal with almost no milk accumulation in the milking bowl. Minimizing the amount of milk in the bowl during milking increases the vacuum reserve and thus minimizes the degree of vacuum fluctuation during normal milking, as well as reducing the free milk available in the claw to be backwashed to the teat ends during abnormal milking events such as slippage of teat cups.
The milking claw of the present invention includes a milk claw bowl with an interior having an inner bottom surface, an inner top surface, and an inner side wall surface between the inner top and bottom surfaces. At least one, and generally four milk inlets are formed in the bowl and open into the interior of the bowl through the inner top surface. These inlets are connected to the milk tubes or hoses leading to the teat cups. A hollow outlet tube is mounted to the bowl with an intake end spaced above and closely adjacent to the bottom surface of the bowl. The outlet tube extends upwardly and sidewardly from the intake end within the interior of the bowl, and extends through the inner sidewall surface to an exit end outside of the bowl. The outlet tube thus extends out of the bowl at a position between the top and bottom of the bowl. The section of the outlet tube which is outside of the bowl is preferably straight to allow unimpeded visual inspection of the weld joint between the outlet tube and the body of the bowl. The outlet tube is preferably curved smoothly from the intake end to the position at which it joins and passes through the inner sidewall surface of the bowl, thus providing smooth flow of milk through the outlet tube with minimum turbulence and minimum pressure drop within the tube. The smoothly curved outlet tube does not collect milk residue and is readily cleaned during the conventional flushing operations for the teat cups after milking has been completed.
While various bowl designs may be utilized, a preferred bowl design includes a cylindrical body formed of stainless steel having two circular open ends, with two circular windows mounted to the open ends of the cylindrical body to close the interior of the bowl. The inner surface of the cylindrical body includes the top and bottom inner surfaces and the sidewall surface. A hanger may be mounted to the cylindrical body above the top inner surface by which the teat cup cluster may be supported at the end of a support arm. Because the top of the cylindrical body does not have the milk outlet tube extending from it, the hanger can be mounted directly to the cylindrical body (typically centered between the milk inlets), rather than being mounted to the outlet tube at a position above the bowl. Because the outlet tube extends out the side of the bowl where it is connected to the milk hose, the other hoses required for milking (e.g., pulsation hose, pulsation hose manifold) and ancillary equipment such as automatic vacuum shutoff, automatic teat end sanitizing controls, etc., have more space available for mounting in a location adjacent the top of the claw and the milk inlets.
Further objects, features and advantages of the invention will be apparent from the following detailed description when taken in conjunction with the accompanying drawings.